1. Technical Field
The present disclosure relates to an antenna, in particular, to a hybrid multi-antenna system and a wireless communication apparatus using the same.
2. Description of Related Art
Now, the communication technology develops rapidly and maturely, and thus people usually use the wireless communication apparatuses to surf the internet and communicate by telephone. Regardless of kinds of wireless communication apparatuses, the wireless communication apparatuses need antennas to receive and transmit the wireless signals at specific frequencies. For example, the indoor and outdoor access points (AP) having antennas are the bridges of the wireless communication apparatuses.
In general, the patch antennas or microstrip antennas have been widely used in outdoor AP due to their characteristics of high directivity and antenna gain.
Some related publications have disclosed the dual-polarized antenna array having a feed-in network and multiple antenna units. The feed-in network of the dual-polarized antenna is used to generate the phase difference of the feed-in signals, such that the dual-polarized radiation pattern can be obtained in the space. Meanwhile, since the multiple antenna units are arranged on the same reflector by the array arrangement, the directivity and gain of the radiation pattern of the dual-polarized antenna can obviously be improved.
However, the aforementioned dual-polarized antenna needs the complex feed-in network and the multiple antenna units to enhance the directivity and antenna gain. In addition, the resonant length of the patch antenna or microstrip antenna is about the half wavelength of the specific frequency. Therefore, owing to its large dimension, the dual-polarized antenna is not suitable for the multiple-input multiple-output (MIMO) multi-antenna communication system.
Regarding each of the multiple antenna units, to decrease the used space of the antenna system, the receiving and transmitting antennas must be arranged compactly. However, due to that the antennas are arranged compactly, the signals received or transmitted by the antennas are mutual coupled when each of the antennas operates in the same or similar band, such that it has the problem of the co-channel interference for the antenna reception. In addition, due to mutual coupling of signals, the system throughput is thus decreased. Taking two parallel dipole antennas as an example, the distance between the two dipole antennas is usually larger than 0.65 wavelength of the operating frequency (i.e. the operating frequency is the specific frequency of the wireless signal), such that the interference of the two dipole antennas is decreased, and the antenna isolation is guaranteed to be less than −15 decibel (dB). However, since the distances between the antennas in the multi-antenna system are limited, the overall dimension of the multi-antenna system is very large, and is unable to be integrated in the thin, light, and small wireless communication apparatus.
Since the strobe feed-in manner is usually used in the patch antenna or microstrip antenna, the location of the feed-in end of the antenna must match the location of the radio signal output end on the system circuit board, and this means that the other antenna is unable to match the same system circuit board.